The force police used to arrest two teenagers on a crime spree was lawful, necessary and justified, an official review has found.

The Children's Commission asked the Independent Police Conduct Authority (IPCA) to look into the arrest of the then 17-year-old Andre Schwaab and his 15-year-old associate at gunpoint in Hira, northeast of Nelson, in 2010.

The Children's Commissioner was upset at the "apparent extreme use of force" Nelson police used to apprehend the pair after seeing a photo of the arrest in the Nelson Mail.

It was especially concerned about a police officer's gun apparently pointed near the teenagers' heads while they were on the ground and handcuffed.

The IPCA has found that at the time the photo was taken, there was no suggestion either young person was attempting to escape or presented any real threat to the public or police.

The IPCA accepted that viewed in isolation, the photograph portrayed a concerning situation.

However, the photo did not accurately convey what Officer A was doing at the time.

The IPCA was satisfied Officer A was in fact three to four metres behind the young people, was on the move, and had his rifle in the low ready position, pointing at the ground.

Given the reality of the fast and fluid police operation, there was no evidence that the actions of Officer A at the time the photo was taken were contrary to law, policy or police firearms training.

The age of the young people was not a factor the police should have given over other more important considerations, most notable of which was the danger they represented to public and police. But it was a factor to be taken into account once an arrest has been achieved.

Schwaab was sentenced to two years and three months jail for more than 20 offences including burglary, unlawfully taking motor vehicles and possession of a firearm following the incident.

His 15-year-old associate was dealt with in the Youth Court.

The pair were arrested at Hira after a five-day crime spree beginning in Christchurch.

Schwaab was driving a stolen Jaguar, had a loaded airgun on the back seat and police said he had "no intention of stopping".

They were confronted by officers armed with rifles, pistols and Tasers at Hira and appeared terrified, and gave up without a struggle, after their car was stopped by road spikes.

Children's Commissioner Dr Russell Wills said the IPCA accepted the photo which led to his predecessor making a complaint was alarming.

"It is the job of the Children's Commissioner to make sure that young people are treated fairly and it was right that concerns were raised in this case.

"I appreciate the thoroughness of the review and accept the conclusions of the IPCA."

Tasman police area commander Superintendent Richard Chambers said he was pleased with the IPCA's findings.

Chambers said the incident illustrated the extremely high level of scrutiny police worked under.

"The situation in question was moving quickly and involved two dangerous offenders who posed considerable risk to public and officer safety.